Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
During operation of a wind turbine, various components of the wind turbine are subjected to various loads. In particular, the shaft coupling the rotor blades and the generator may be subjected to various loads, such as axial and bending loads. Deflection of the shaft due to these loads may thus frequently occur during operation of the wind turbine. The bending moment induced on the shaft due to such loading is a particularly critical variable, and in many cases should desirably be reduced during operation of the wind turbine.
However, currently known systems and methods for measuring shaft deflection, such as bending moment, may not be accurate and/or may be poorly located. For example, proximity probes may be mounted to a flange on the shaft to monitor displacement. However, such probes must be located in relatively small, inaccessible areas, making them difficult to install and maintain. This can result in inaccuracy and poor reliability. Another example involves sensors mounted to the shaft itself. However, such mounting requires relatively expensive and unreliable telemetry systems for obtaining and transmitting data. Further, currently know systems and methods can result in confounding of various types of deflection, such as torsional moment versus bending moment.
Thus, an improved system and method for adjusting the bending moment of a shaft in a wind turbine is desired. For example, a system and method that provide more accurate and reliable measurements and adjustments would be advantageous.